Gastrula

4 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Gastrula \Gas"tru*la\, n.; pl. {Gastrul[ae]}[NL., dim. fr. Gr. ?
     the stomach.] (Biol.)
     An embryonic form having its origin in the invagination or
     pushing in of the wall of the planula or blastula (the
     blastosphere) on one side, thus giving rise to a
     double-walled sac, with one opening or mouth (the blastopore)


     which leads into the cavity (the archenteron) lined by the
     inner wall (the hypoblast). See Illust. under {Invagination}.
     In a more general sense, an ideal stage in embryonic
     development. See {Gastr[ae]a}. -- a. Of or pertaining to a
     gastrula.
     [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Planula \Plan"u*la\, n.; pl. {Planul[ae]}. [L., a little plane.]
     1. (Biol.) In embryonic development, a vesicle filled with
        fluid, formed from the morula by the divergence of its
        cells in such a manner as to give rise to a central space,
        around which the cells arrange themselves as an envelope;
        an embryonic form intermediate between the morula and
        gastrula. Sometimes used as synonymous with {gastrula}.
        [1913 Webster]
  
     2. (Zool.) The very young, free-swimming larva of the
        c[oe]lenterates. It usually has a flattened oval or oblong
        form, and is entirely covered with cilia.
        [1913 Webster]

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  Stomapoda \Sto*map"o*da\, n. pl. [NL. See {Stoma}, and {-poda}.]
     (Zool.)
     An order of Crustacea including the squillas. The maxillipeds
     are leglike in form, and the large claws are comblike. They
     have a large and elongated abdomen, which contains a part of
     the stomach and heart; the abdominal appendages are large,
     and bear the gills. Called also {Gastrula}, {Stomatopoda},
     and {Squilloidea}.
     [1913 Webster]

From WordNet (r) 2.0 [wn]:

  gastrula
       n : double-walled stage of the embryo resulting from
           invagination of the blastula; the outer layer of cells is
           the ectoderm and the inner layer differentiates into the
           mesoderm and endoderm
       [also: {gastrulae} (pl)]